Divisi
Bollworm complex
· Insect
Photo: David McClenaghan, CSIRO · CC BY 3.0
Bollworms are a group of caterpillars that attack the fruiting parts of the crop rather than the leaves. The main one is the African bollworm (Helicoverpa armigera), joined by the spiny bollworm (Earias species) and the pink bollworm (Pectinophora gossypiella). Dull, night-flying moths lay their eggs on flowers, growing tips and young fruit; the caterpillars then bore into the cotton bolls, or into the pods and fruit of beans, cowpeas, pigeon peas, chickpeas, soybeans, tomatoes, peppers and okra — eating the seed and lint you were going to sell.
Ben Sale from UK · CC BY 2.0 
Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org · CC BY 3.0 us
Why it matters
Bollworms go straight for the part you sell — the bolls on cotton, and the pods and fruit on beans, cowpeas, pigeon peas, tomatoes, peppers and okra. A bad attack can eat up to 60% of your harvest — well over half. And one caterpillar does not stop at one fruit: it bores from pod to pod, fruit to fruit, and once it is tucked inside, no spray can reach it and the rot is already done. That is why you must catch it early — as eggs and tiny caterpillars on the outside, before it bores in.
When to act
Spray when about 1 in 4 plants carries eggs or young larvae, or when 5-10% of squares/bolls show fresh boreholes.
This guidance is general, compiled from published agronomic references including FAO and CABI. Thresholds and timing shift with your crop, your variety and the season.
In much of the region a spray is simply called mushonga — medicine. But a chemical group you cannot name is one you cannot rotate, and a product you did not write down has no pre-harvest interval you can observe. Mushonga, and other farming words →
The full bollworm complex field guide
- Identify it
- Scout for it
- Control it
20 field-guide sections in the app
The full guide to bollworm complex — every symptom to check, how and when to walk your field looking for it, and the controls that actually work, ranked. Built into your crop plan, so you are told to look before it costs you a harvest.
Crops it affects
Frequently asked questions
How do I identify bollworm complex?
Look at the fruit, not the leaves. The first sign is round bore-holes in the cotton bolls (the pods that hold the lint and seed), or in the pods and fruit of beans, cowpeas, tomatoes, peppers and okra — usually with wet, crumbly droppings (frass) pushed out at the hole. Buds, squares (the flower buds) and young bolls or pods drop off the plant, and if you cut one open the inside is hollow, stained or rotten.
When should I take action against bollworm complex?
Spray when about 1 in 4 plants carries eggs or young larvae, or when 5-10% of squares/bolls show fresh boreholes.
How do I control bollworm complex?
Prevent first — grow a resistant variety. On cotton, plant Bt cotton where it is available: a variety that carries a natural protein from the soil germ Bacillus thuringiensis (Bt) which kills the young worm as soon as it bites. Always keep a refuge — a strip of ordinary non-Bt cotton nearby — so the few surviving worms breed with normal ones and the pest does not turn resistant. On beans, peas and vegetables, choose any recommended tolerant variety your extension officer names.
Which crops does bollworm complex affect?
Among the crops covered here: Chickpea, Common bean, Cotton, Cowpea, Hot pepper, Okra, Pigeon pea, Soybean.
Catch it before it costs you a harvest
Divisi builds scouting into your crop plan — it tells you when to walk your field, what to look for at that stage, and what to do when you find it. Free for farmers, works offline.
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